Power supply



FIG. 1 is a front view of a power supply showing our new design;

FIG. 2 is a top view thereof;

FIG. 3 is a side view thereof;

FIG. 4 is a rear view thereof; and,

FIG. 5 is a perspective view thereof.

The broken lines in the drawings depict portions of the power supply that form no part of the claimed design. 

CLAIM The ornamental design for a power supply, as shown and described. 